OFInflateStream.h

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#import "OFStream.h"

OF_ASSUME_NONNULL_BEGIN

#define OF_INFLATE_STREAM_BUFFER_SIZE 4096

@interface OFInflateStream: OFStream
{
#ifdef OF_INFLATE_STREAM_M
@public
#endif
    OFStream *_stream;
    uint8_t _buffer[OF_INFLATE_STREAM_BUFFER_SIZE];
    uint_fast16_t _bufferIndex, _bufferLength;
    uint8_t _byte;
    uint_fast8_t _bitIndex, _savedBitsLength;
    uint_fast16_t _savedBits;
@protected
    uint8_t *_slidingWindow;
    uint_fast16_t _slidingWindowIndex, _slidingWindowMask;
    enum {
        OF_INFLATE_STREAM_BLOCK_HEADER,
        OF_INFLATE_STREAM_UNCOMPRESSED_BLOCK_HEADER,
        OF_INFLATE_STREAM_UNCOMPRESSED_BLOCK,
        OF_INFLATE_STREAM_HUFFMAN_TREE,
        OF_INFLATE_STREAM_HUFFMAN_BLOCK
    } _state;
    union {
        struct {
            uint_fast8_t position;
            uint8_t length[4];
        } uncompressedHeader;
        struct {
            uint_fast16_t position, length;
        } uncompressed;
        struct {
            struct huffman_tree *litLenTree, *distTree;
            struct huffman_tree *codeLenTree, *treeIter;
            uint8_t *lengths;
            uint_fast16_t receivedCount;
            uint_fast8_t value, litLenCodesCount, distCodesCount;
            uint_fast8_t codeLenCodesCount;
        } huffmanTree;
        struct {
            struct huffman_tree *litLenTree, *distTree, *treeIter;
            enum {
                OF_INFLATE_STREAM_WRITE_VALUE,
                OF_INFLATE_STREAM_AWAIT_CODE,
                OF_INFLATE_STREAM_AWAIT_LENGTH_EXTRA_BITS,
                OF_INFLATE_STREAM_AWAIT_DISTANCE,
                OF_INFLATE_STREAM_AWAIT_DISTANCE_EXTRA_BITS,
                OF_INFLATE_STREAM_PROCESS_PAIR
            } state;
            uint_fast16_t value, length, distance;
            uint_fast16_t extraBits;
        } huffman;
    } _context;
    bool _inLastBlock, _atEndOfStream;
}

+ (instancetype)streamWithStream: (OFStream*)stream;

- initWithStream: (OFStream*)stream;
@end

OF_ASSUME_NONNULL_END